Question: $ { \left[\begin{array}{rr}{0} & {-2} \\ {-1} & {-1} \\ {0} & {0}\end{array}\right]-\left[\begin{array}{rr}{-2} & {2} \\ {2} & {4} \\ {1} & {-1}\end{array}\right] = {?} } $
Solution: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{0}-{-2} & {-2}-{2} \\ {-1}-{2} & {-1}-{4} \\ {0}-{1} & {0}-{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{2} & {-4} \\ {-3} & {-5} \\ {-1} & {1}\end{array}\right]}$